1. Field of the Invention
The present invention relates to drum type washing machines, and more particularly, to a structure of driving part of a direct coupling type drum type washing machine.
2. Discussion of the Related Art
In general, in a drum type washing, the washing is performed by using friction between a drum rotated by driving force of a motor and laundry in a state detent, washing water, and the laundry are introduced into the drum, and gives almost no damage to the laundry, has no entangling of the laundry, and can provide a pounding, and rubbing washing effect.
A related art drum type washing machine will be described briefly with reference to FIG. 1.
FIG. 1 illustrates a longitudinal section of a related art drum type washing machine, provided with a tub 2 on an inside of a cabinet 1, a drum 3 rotatably mounted at a center of an inside of the tub 2.
Under the tub 2, there is a motor 5a coupled to a motor pulley 18 with a shaft. There is a drum shaft connected to a rear of the drum 3, having a drum pulley 19 mounted thereon. The drum pulley 19 on the drum shaft and the motor pulley 18 coupled to the motor 5a are coupled with a belt 20, a power transmission element.
There is a door on a front of the cabinet 1, with a gasket 22 between the door 21 and the tub 2.
In the meantime, between the cabinet 1 at an inside of an upper portion thereof and the tub 2 at an upper side of an outside circumference thereof, there are hanging springs 23 for hanging the tub 2, and between the cabinet 1 at an inside of a lower portion thereof and the tub 2 at an lower side of an outside circumference thereof, there are friction dampers 24 for attenuating vibration of the tub 2 occurred at the time of spinning.
However, the related art drum type washing machine, transmitting driving force from the motor 5a to the drum 3 through the motor pulley 18, the drum pulley 19, and the belt 20 coupling the motor pulley 18 and the drum pulley 19, has the following disadvantages.
Because the driving force is transmitted to the drum 3 from the motor 5a, not directly, but through the motor pulley 18, the drum pulley 19, and the belt 20, there is an energy loss occurred in a process of driving force transmission.
Moreover, because the driving force is transmitted to the drum 3 from the motor 5a, not directly, but through many components, such as the motor pulley 18, the drum pulley 19, and the belt 20, there is much noise occurred in the process of power transmission.
Because many components, such as the motor pulley 18, the drum pulley 19, and the belt 20, for transmission of the driving force from the motor 5a to the drum 3, many assembly man-hours are required.
In proportion to a number of components required for transmission of the driving force from the motor 5a to the drum 3, number and frequency of fault occurrences become greater.
In summary, transmitting driving force from the motor 5a to the drum 3 through the motor pulley, the drum pulley, and the belt indirectly, the related art drum type washing machine is liable to cause faults, and noise, has many energy wasting factors, and results in poor washing performance.
Along with this, because of the tub 2 formed of stainless steel, the related art drum type washing machine is expensive, has a poor formability, and is heavy.
Consequently, in order to solve the problems of the related art drum type washing machine, a direct coupling type drum type washing machine with a BLDC motor is suggested.
However, since the direct coupling type drum type washing machines with BLDC motors developed up to the present time still has various disadvantages and problems in view of structures, process lines, or operations, there are requirements for direct coupling type drum type washing machines of new structures.
That is, the related art drum type washing machine has much waste of materials, such as core, and so on, in fabrication of the motor, or has a problem of complicate fabrication process, and strengths of the tub or the stator mounted thereon are weak for mounting the motor on the tub, to fail in attenuating vibration and noise, effectively.
Particularly, the washing machine which rotates the drum directly with the BLDC motor has the stator mounted on a rear side of the tub, directly. In a case of the motor for a large capacity drum type washing machine, with weight of the stator only being 1.5 kg or more, and a spinning speed of 600˜2000 RPM, a joining portion of the stator and the tub is broken due to weight of the stator, and vibration, shake, and deformation of the rotor 5 at the time of spinning.
That is, in a case of a drum type washing machine which employs a BLDC motor with a stator secured to a rear wall of the tub, since an axis direction of the stator is substantially parallel to a floor, vibration caused at the time of operation of the washing machine causes heavy damage at the joining portion of the stator with the tub rear wall.
In order to prevent this, in fabrication of stator core in the related art, a metal sheet is pressed, to form Ts and base portion, and, at the same time with this, projections 500 are formed on an opposite side of the Ts for joining, and a plurality of which are stacked, to form a stator core as shown in FIG. 2.
However, fabrication of above SC (Sectional type core) of the stator, not only is complicate, but also has waste of much material.
For reducing waste of material, and simplifying the fabrication process, though so called helical type core is favorable, in which a steel plate having the Ts and the base is stacked while turning the steel plate in an helix, the helical type core has disadvantage in that the projections 500 can not be formed toward an inner side of the core for joining the stator to the tub because a steel plate punched in a form of a stripe is required to be bent in a helix in fabrication of the helical type core.
This is because the projections 500 formed toward an inner side of the core make the stacking of the core by the turning the core in a helix impossible due to too great width of the core.
Consequently, a stator structure is required, in which a function identical to the projections of the sectional core SC is made to be performed, not by the core itself, but by other part, for enabling application of the helical type core HC.
For reference, the reason that securing of an adequate rigidity of the projections each having a fastening hole for fastening the stator to the tub is important is as follows.
The washing machine which rotates the drum directly with the BLDC motor has the stator mounted on a rear side of the tub, directly. In a case of the motor for a large capacity drum type washing machine, with weight of the stator only being 1.5 kg or more, and a spinning speed of 600˜2000 RPM, a joining portion of the stator and the tub is broken due to weight of the stator, and vibration, shake, and deformation of the rotor 5 at the time of spinning.
That is, in a case of a drum type washing machine which employs a BLDC motor with a stator secured to a rear wall of the tub, since an axis direction of the stator is substantially parallel to a floor, vibration caused at the time of operation of the washing machine causes heavy damage at the joining portion of the stator 6 with the tub rear wall.
Thus, securing of an adequate rigidity of the projections each having a fastening hole for fastening the stator 6 to the tub is very important.
Moreover, when an axis direction of the stator is parallel to the ground, with a heavy stator over 1.5 kg overhung therefrom, there has been breakage of a portion of the tub the stator is fastened thereto caused by the vibration.